Industry Awaits Clarity from FAA on Datalink Standard

Three industry teams are vying for the FAA’s Data Communications Integrated Services (DCIS) contract to provide a nationwide data network between ATC facilities and datacomm-equipped aircraft, with a contract award anticipated in June. Even as it was evaluating these proposals, however, the FAA had not decided which datalink standard to implement.

Ultimately, pilots and controllers in the U.S. and elsewhere will communicate via the Aeronautical Telecommunications Network (ATN), a communications backbone connecting aircraft, airline operations centers and ATC facilities. A global datalink standard to access the network known as ATN Baseline 2 (ATNB2) is under development by RTCA Special Committee 214 in the U.S., working jointly with Eurocae Working Group 78 in Europe. Nevertheless, the U.S. and Europe are pursuing different evolutionary paths to reach that end state in the 2020s, with implications for regional carriers and business aviation.

The U.S. plans to leverage Future Air Navigation System (Fans) 1/A-standard avionics already deployed in Boeing and Airbus aircraft for oceanic controller-pilot datalink communications to communicate in continental airspace. In Europe, new aircraft must be equipped with ATN-compliant VHF Digital Link Mode 2 (VDL2) technology by 2014 under Eurocontrol’s Link 2000+ program. Importantly, Fans-equipped aircraft are exempt from the mandate, allowing for their continued operation in European airspace.

The rub is that regional airliners and business and GA aircraft in the U.S. are generally not equipped with Fans avionics, so would not benefit when the capability for data communications is introduced at airport towers from 2015 to 2018, followed by en route ATC facilities. The FAA in the DCIS solicitation said it is investigating the use of an interim standard–ATN Baseline 1 (ATNB1) or an augmented version of it–that would allow other aircraft to send and receive data messages during the transition to ATNB2.

Airbus and Boeing have said they oppose the introduction of ATNB1 because it is not an “integrated” standard, or one that allows for the exchange of digital messages between ground automation systems and aircraft flight management systems (FMS).

“Integrated datacomm provides a mechanism to avoid gross navigational errors and is a pre-requisite to” trajectory-based operations (TBO), the airframers stated in a joint letter to the RTCA NextGen Advisory Committee in September. “…Resources applied to deploy ATNB1 in parallel with Fans 1/A would reduce those available for achieving (initial operational capability) of en route services on schedule in 2018 and would jeopardize deployment of early TBO capabilities. If additional resources are to be allocated to ATN deployment, they should be applied to moving ATNB2 implementation forward to 2018 to coincide with European deployment.”

Scott Foose, Regional Airline Association (RAA) senior vice president of operations, said clarity on datacomm awaits the recommendations of the NextGen Advisory Committee (NAC), which the FAA has tasked with developing a “roadmap” for data communications. “Until then, the roadmap for datacomm equipage is unclear,” Foose said in response to an AIN query. “However, many regional airlines are already equipping their aircraft with advanced, digital communications avionics that we believe will provide an excellent platform for the transition to ATN Baseline 2. RAA and our airline members look forward to reviewing the equipage roadmap when it is available.”

The NAC datacomm roadmap task group presented its recommendations to the full committee February 3. According to a draft of the recommendations, the NAC will advise the FAA to support a mix of datalink standards.

“We knew that a significant number of aircraft in the business and general aviation community, as well as some legacy mainline and regional aircraft, would never be able to accommodate Fans 1/A+ or integrated ATN avionics,” the draft document states. “On the other hand, many of the newer regional aircraft have VDL2 and a relatively simple and inexpensive upgrade path to non-integrated ATN capability. … This reality is the basis upon which we concluded that a recommendation for ATNB2 with a non-integrated subset of ATN Baseline 1 services provided the most reasonable path to success.”

Representatives of the industry teams pursuing the DCIS contract–headed respectively by Lockheed Martin, ITT Exelis and Harris–said the standards issue shouldn’t delay deployment of the planned data network. “What [the FAA] asked you to do in your proposal was to talk about the future of ATN and what you would do about it,” said Diane Desua, Lockheed Martin director of NextGen strategy and en route support. “[It will] let the contract and probably use us as an integrator to help them make those decisions.”